Mower stalling under light load

[YawningAngel]

Hi all!

I have a Mountfield SP414, equipped with an RS100 motor - a generic 100cc Honda-clone with an auto-throttle & no choke.

It starts easily and idles smoothly, but when I start cutting grass it stalls within about 10'. It seems as if the auto-throttle is not reacting to the load (due to grass cutting), so in effect, it it truing to cut at a constant idle...and not surprisingly stalling fairly quickly.

I have done all the usual checks....fresh fuel, clean air filter and even a full strip down or the card (incl an hour in a hot ultrasonic cleaner followed by a blow through all orifices with an air line)....all to no avail.

When running, if I manually actuate the auto-throttle, the engine revs up well...it just doesn't seem to want to do so itself...

any ideas...?

cheers

Paul

 

[bertsmobile1]

start the mower then get down and move the governor lever when you push it it should spring back. Mind your fingers.
If it does that and the engine speed responds then I expect the governor arm has slipped on the governor shaft
AS the shaft rotates it CLOSES the throttle plate in the carb
At rest ( engine off ) the spring which connects the throttle control pulls the governor arm fully open to open the throttle fully
SO it probably needs to b adjusted by loosening the clamp bolt on the bottom of the arm.
w\hold the governor arm so the throttle butterfly is fully open then turn the governor shaft in the direction that will fully close the throttle butterfly then tighten the clamp with your 3rd hand.

 

[YawningAngel]

Thanks! will give that a try